= Ian Mann
{disambiguate=metrology}
{c}
\b[Ian Mann] is a metrology and laboratory-quality specialist credited with <Brian Brookman> as co-editor of the 2021 third edition of <Selection, Use and Interpretation of Proficiency Testing (PT) Schemes by Brian Brookman and Ian Mann>. The editorial page identifies him with SAS in Switzerland. This identifies the proficiency-testing author without attributing the careers of other people named Ian Mann to him.<Selection, Use and Interpretation of Proficiency Testing (PT) Schemes by Brian Brookman and Ian Mann>[Editorial page, PDF p. 3, editor affiliation and recommended citation]{ref}
The guide connects <proficiency testing> with practical decisions about laboratory measurements. Its selection criteria ask whether a scheme's material, <measurand>, concentration range and assessment approach fit the laboratory's actual work. A comparison using an unsuitable material can fail to test the procedure for which competence is being assessed.<Selection, Use and Interpretation of Proficiency Testing (PT) Schemes by Brian Brookman and Ian Mann>[Section 5.4, fitness for purpose of a selected scheme]{ref}
An original example illustrates why interpretation needs the assessment criterion. For a participant result $x=102$, assigned value $x_{\rm pt}=100$ and <standard deviation for proficiency assessment> $\sigma_{\rm pt}=1$ in compatible units, the <proficiency-test z-score> is
$$
z=\frac{x-x_{\rm pt}}{\sigma_{\rm pt}}=2.
$$
A scheme using $\sigma_{\rm pt}=2$ would give $z=1$ for the same result. The result and its difference from the reference did not improve; the assessment scale changed. The chosen <standard deviation for proficiency assessment> must therefore be read with the score.
A participant's reported <standard uncertainty> answers another question: how uncertain is that participant's measurement result? It is not automatically the scheme's performance criterion. The guide separates evaluation scores, assessment spread and laboratory investigation of unexpected results.<Selection, Use and Interpretation of Proficiency Testing (PT) Schemes by Brian Brookman and Ian Mann>[Sections 7.2.4 and 8.2.3–8.3]{ref} Mann's documented editorial contribution is to this shared measurement-quality guidance; no separate invention or personal experimental result is implied.
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